When importing svg from inkscape, losses of color and definition
Blender being a 3D modeling application doesn't really work like a 2D vector drafting application like Inkscape, there is no Z ordering or layers to tell what stays above what, like one would in an illustration program.

What you see in you image is not loss of color or definition, nothing is wrong with your shapes, what you are seeing it is simply the imported shapes overlappingeach other at Z=0 height and causing faces to glitch.

This is a well known issue with rendering 3D scenes with overlapping geometry often called Z-Fighting

Think how these shapes would be built in the real world, there can't possibly be two objects be occupying the same physical space. You simply have to "subtract" or remove the shapes from each other so there are no overlapping parts.

For example make a copy of your "yellow logo" part and joint it with Ctrl + J to the white "cone base" part, so there is a whole there with the same outline, where the yellow logo can be seen through. Same for all other parts, purple background should have a whole in the center shaped like the white cone, and so on.

Before you proceed consider this:

Are you planing to make this cone three dimensional with an actual cone shape?
Have in mind that you will have a very hard time doing that from a bezier curve object, or even from a mesh object created from those imported SVGs. Blender doesn't deal with that very well at all because of how bezier curve geometry is generated.

Consider exporting your design from Inkscape as a PNG image and using that as a texture on your cone instead. Model a cone from a mesh in Blender directly, it will be a lot easier and produce better results.